Method of making drilling jars



Aug. 27, 1929. p ARBQN 1,725,842

METHOD OF MAKING DRILLING JARS Filed June 2, 1925 2 Sheets-Sheet 2 Patented Aug. 27, 1929.

UNITED STATES masts PATENT OFFICE.

PAUL AEBON, OF TULSA, OKLAHOMA; FIDELITY NATIONAL. BANK AND TRUST COM- PANY, OF KANSAS OETY, MISSOURI, AND LOENE M. MCLEOD, OF TULSA, OKLAHOMA, EXEOUTORS OF THE ESTATE OF SAID PAUL ARBGN, DECEASED, ASSIGNORS TO PAUL ARBON & COMPANY, OF TULSA, OKLAHOMA, A CORPORATION OF OKLAHOMA.

METHOD OF MAKING DRILLIIIG- JARS.

Application filed. June 2, 1925. Serial 1T0. 34,385.

This invention relates to the production of drilling ars and more particularly to an improved method of manufacturing such jars in such a manner as to eliminate any possible weak points in the assembled construction.

For many years workers in the well drilling art have -suffered great inconvenience owing to the breaking of the jar during the drilling operation. This was due mainly to the fact that the movable sections of the ar were connected together by threaded, riveted or welded joints, which formed points of weakness. Efforts have been made for many years to overcome this defect, but so far as I am aware no jar has been produced to date which proved entirely satisfactory. In my patent application 699,938 filed March 17, 1924;, I have disclosed a numher of methods of making drilling j and the jars formed thereby, while better than the jars known prior to that invention, have not proved as successful as the ars made in accordance with my present method. I have discovered that jars of the character described in my said prior application are greatly improved by making the same of a special alloy and subjecting the parts to a very careful and somewhat elaborate heat treatment.

Therefore, the primary object of this invention is to provide an improved method whereby drilling jars may be inexpensively and easily manufactured. Such jars are of such construction that the stress and strain on the parts will be properly accommodated and in which the liability of breakage is negligible, it being obvious to those versed in the art that the rupture of an element of the jar during a drilling operation is ex pensive both in time and labor and may result in the total destruction of a well.

Another object of the invention is to furnish a novel method for heat treating the parts in order to obtain maximum hardness combined with safety to the wearing parts, and also combined with very ductile and comparatively soft joints.

With the foregoing objects outlined and with other objects in View which will appear as the description proceeds, the invention consists in the novel features hereinafter described in detail, illustrated in the accompanying drawing and more particularly pointed out in the appended claims.

Referring to the drawing:

Figure 1 is a side view partly in section of one form of made in accordance wit-h the present invention.

Fig. 2 is a similar view of a portion of the jar during manufacture.

Fig. 3 is a transverse sectional view taken on line 38 of Fig. 2.

Fig. 4 is a similar View taken on line l4c of Fig. 1.-

Fig. 5 is a diagram to show the effect of tempering, after oil-hardening at 820 C.

In Figs. 1 to at inclusive, 1 designates the outer or socket portion of the jar and 2 inclicates the inner or stem portion of the jar. The outer section is provided with a slot 3 which extends from the body 4 of the socket to the head 5 of the same, and the head has a central opening 6 for a purpose hereinafter described. The stem section 2 is provided with a T-shaped head 7 consisting of the cross head 8 and the stem 9, the latter being integral with the body portion 10 through the medium of the tapered part 11.

Before the sections are assembled the annular head 5 has the cross section shown in Fig. 3 and the opening therein is of substantially the same shape as the head 8 of the stem section. Due to this construction the T-shaped head 7 may be inserted through the hole 6 and into the slot 8. Before the insertion, the head 5 is heated and after the insertion blocks 12 are inserted from opposite sides of the slot until they abut against the stem 9, as shown in Fig. 2. After this the enlargements 13 on the head are hammered inwardly to fill the spaces 14, so that the head assumes the circular shape shown in Fig. 4c. The heated head is then allowed to cool and the shrinkage due to the cooling produces the necessary working clearance. Should it be found that the stroke of the jar is insufiicient, portions of the tapered part 11 may be machined oif. During the finishing operation, the movable parts may, of course, be clamped or wedged into a fixed position.

A jar formed in this manner has previously been disclosed in my said application Ser. No. 699,938, and I have improved the same in the following particulars. The

steel employed has the following specification by analysis:

Minimum Maximum Per cent Per cent Carbon .28 32 Silicon... .35 04 0-1 4. O0 .70

In addition to making the jar sections of this alloy, I also prefer to provide the socket section with circulating holes 15 for mud clearance and to form mud clearing flutes or grooves 10 in the stem. Before forging, the steel is machined all over to remove surface defects, thus insuring as far as possible, soundness in the steel. The is forged in two sections of the kind disclosed in Fig. 2, the part 2 being forged to the finished shape except for a machining allowance, while the part 1 is left bell-mouthed for the length of the head 5 in order to permit the head 8 of the inner member to be inserted in the slot 3. The member 1 is machined at the head 5 in such a way as to allow for the displacement of the material when the head is closed in on the stem 9.

In order to obtain the best results from an alloy steel, such as that given above, it is essential that a special heat treatment should be given. In setting forth the following heat treatment, it may be stated that the primary object is to obtain the maximum hardness combined with safety to the wearing parts and to produce very ductile and comparatively soft joints.

After the two forgings, which are to form the jar sections, are made, they are carefully annealed in order to soften them sufficiently to be easily machined. No further heat treatment is made until the jars are in their final form except for the machining of the joints. They are then oil-hardened to bring the steel to a maximum stress of approximately 80 tons to the square inch. After this, the two ends are inserted in turn in a furnace and tempered at 630 6., which leaves them in the most ductile condition in which it is possible to put this steel. A still further heat treatment is then given by heating the whole jar in a bath of oil at 200 G, which materially increases the ductility and resistance to shock of the wearing parts.

The diagram shown in Fig. 5 will be of interest in explaining the reasons for the heat treatment given above. The graphs shown in this figure were obtained from a series of test pieces, all of which were oilhardened in the same manner as the jars. Each test piece was then tempered at varying temperatures between 0 C. and 700 C.

The graphs give physical test results after this tempering. Taking the graph representing maximum stress, it will be seen that this remains practically constant until the test piece, which was tempered at 200 C. was reached, while the yield point which is perhaps of more importance than the maximum stress actually rises when tempered at this temperature, as compared with the test pieces oil-hardened only. At the same time, referring to the elongation, reduction of area and Izod graphs (the latter representing the energy absorbed by the steel in breaking a nicked test piece by a blow from a pendulum hammer, and being obviously an important characteristic for steel used in jars), it will be seen that all three have very considerably greater values at 200 C. than at 0 C. It is therefore, this treatment which I have given to the working parts of the ar.

Now looking at the position of the graphs of the test pieces tempered at 600 (3., it will be seen that the maximum stress has dropped to approximately tons per square inch, the yield point to 55 tons per square inch, while elongation, reduction of area and Izod, have all of them risen enormously. While if the temperature is raised still further to approximately 650 0., the minimum of hardness and maximum of ductility is obtained. It is not absolutely safe, however, to use this temperature, as just above it there is a rapid rise in the hardness and drop in the ductility. The jars are-therefore tempered at the ends at between 600 C. and 630 C. i

There is only one further point which calls for any comment and that is that the test pieces were, of course, of only very small diameter, and as a consequence oil-hardening was very much more effective than in the case of jars, owing -to the more rapid cooling. If similar tests are made with jars, the maximum stress graph will start at approximately 80 tons per square inch instead of 112, and will drop to approximately 50 tons per square inch instead of 60 at the softest point. The shape of the graphs, however, Will be the same. As regards elongation, reduction of area and Izod, these will remain practically the same in either case.

The tensile strength of the alloy steel used in the improved construction is approximately 50% greater than that of the best steel used for welded jars. The total load required permanently to stretch a nine inch jar made in accordance with the present invention is 972 tons, compared with 562 tons of a nine inch welded jar. The construction is such as to eliminate any possibility of distortion, and in consequence the common danger of locking is absent.

From the foregoing it is believed that the method of manufacture and the construction of the jars may be readily understood and I am aware that various changes may be made in the details disclosed without departing from the spirit of the invention as expressed in the claims.

What I claim and desire to secure by Letters-Iatent is:

1. In the production of drilling jars, machining two work pieces all over to remove surface defects, then forging the work pieces to provide a socket section and a stem section, then annealing said sections to soften them sufficiently to be easily machined, and then oil-hardening the sections to bring the steel to maximum hardness.

2. In the production of drilling jars, forging two work pieces to produce a socket section and a stem section, then annealing the sections to soften them suficiently to be easily machined, then oil hardening the sections to bring the steel to a maximum stress of approximately 80 tons per square inch, then tempering the sections to approximately (330 C. to put the sections in the most ductile condition possible, and then heating the whole jar in a bath of oil at 200" C. to materially increase the ductility and resistance of the steel.

3. In the production of drilling ars, 101ging a plurality of steel work pieces to form a socket section and a stem section, annealing the sections to soften them suiiiciently to be easily machined, then oil-hardening the sections to bring the steel to a maximum stress of approximately 80 tons per square inch, and subsequently inserting the stem section 111 the socketsection and distorting a portion of one of said sections to interlock the sections.

4. In the production of drilling jars, forging a plurality of work pieces of steel to form a socket section and a stem section, subsequently oil-hardening the sections to bring the steel to a maximum stress of approximately 80 tons persquare inch, afterwards tempering the sections substantially but below 630 (1, then subjecting the sections to a heat treatment in a bath of oil at approximately 200 C.

5. In the production of drilling ars, forging two alloy steel work pieces containing carbon, silicon, manganese, sulphur, phosphorus, nickel and chromium to form a socket section and a stem section, inserting the stem section in the socket section after the sections have been oil hardened, and distorting a portion of one of the sections to interlock the sections together.

6. In the production of drilling jars, forging two work pieces of alloy steel consisting of carbon, silicon, manganese, sulphur, phosphorus, nickel and chromium, annealing said sections to soften them sufficiently to be easily machined, then oil-hardening the sections to bring the steel alloy to a maximum stress of approximately 80 tons per square inch, then tempering die sections at approximately 630 (3., subsequently heating the sections in a bath of oil at approximately 200 (1., and assembling said sections.

I 7. A method as claimed in claim 6 in which the work pieces are machined all over before they are forged.

In testimony whereof I affix my signature.

PAUL ARE ON. 

